A distinction is needed between different meanings of one word and different individuals covered by one meaning.
“Student” has one ordinary meaning that may apply to many students. Multiplicity of instances does not by itself create lexical homonymy.
A genuinely homonymous word, by contrast, has been assigned to more than one distinct concept. The central question becomes which of those concepts is intended, not how many individuals fall under an already chosen concept.
Thus a mushtarak requires selection of sense first, whereas the study of general expressions deals with the range of individuals included within a sense already known.